1. Field of the Invention
The present invention relates to numismatic detectors, and is particularly concerned with detectors of the type used by coin collectors and others to identify particular coins and as an aid in the grading of such coins in the determination of their actual current value.
2. Prior Art
It has long been recognized in the field of numismatics that the value of a coin is largely dependent upon the characteristics of the coin itself. For example, some coins have significant value because of particular minting flaws. Others, may have increased worth, because of the condition of the coins, in comparison with the condition of other coins of like mintage. In almost all instances, where a numismatic coin is to be traded, or sold, it is important that the coin can be properly graded so that the seller and buyer can arrive at a proper value determination. In the past gradings used have included good, very good, fine, very fine, extremely fine, and about uncirculated. Rare coins have also been graded as fair, or about good. A coin graded according to these categories, has definite value meaning to a coin collector. However, it has long been recognized that the determination of the specific one of the categories to be applied to any given coin is a subjective matter, involving the judgment and opinion of the buyer and seller. Generally, of course, the seller is attempting to have the coin graded as high as possible and the buyer desires the coin to be graded lower for purposes of the transaction. The American Numismatic Association has established a more precise standard grading schedule i.e., the Sheldon Mint Grading System, which uses a number system wherein coins are rated on an increasing number valuations, i.e. 40, 45, 50, and 55 and MS 60, MS 61, . . . MS 70 are used to indicate increasingly better quality in the coins so graded. Certain coins, because of their particular value, or particular characteristics, become well known in the numismatic field, as they are traded or sold to one collector or another.
Devices used to provide a general identification of the coin, have long been available for use in coin operated vending machines, and the like. Such coin testing devices may incorporate apparatus that can be of value to the numismatic field. For example, U.S. Pat. No. 4,184,366, discloses an apparatus for testing the diameter, composition, and thickness of a coin. It may also test the weight of the coin. These data can be very helpful, to a coin collector. Also, U.S. Pat. No. 4,546,868, used optical devices which detect factors, such as diameter, thickness, and weight of rolling coins to determine whether or not they are acceptable to vending machines.
Other devices, more specifically developed for the numismatic field, include U.S. Pat. No. 3,349,612, for a "Silhouette Coin Grader" wherein a coin is positioned within a holder and a slide having transparencies showing a coin of the same type are passed over so that the surface of the coin being tested can be compared against graded surfaces shown in the transparencies to determine the actual grade of the coin. U.S. Pat. No. 3,728,795, shows a "Coin Degree Finder" that can be used to readily determine to what degree the opposite side of a coin is off clockwise or counterclockwise respective to the other side of the coin. U.S. Pat. No. 4,134,209, discloses a device and method for measuring the die rotation error of coins and is important to coin collectors, since such errors occur during the process of coining the money.
U.S. Pat. Nos. 4,128,158 and 4,226,323 to Joseph L. Dautremont, disclose precision coin analyzers for numismatic applications. The devices disclosed in these patents, use electrical circuitry to separate genuine coins from counterfeit coins. The testing devices are adaptable to use in vending machines, and further are adapted to use for those purchasing bullion coins. The devices are particularly adaptable for use in detecting coins fabricated to have a valuable metal exterior coated on a base metal disc.
It has also been recognized that there is a need for apparatus to clearly identify coins so as to prevent fraud during the sale of such coins, and to allow them to be identified in the event of recovery after a theft. Thus, U.S. Pat. No. 4,058,820, discloses a method and apparatus for obtaining coin identification photographs and for coding such photographs for registration and picture identification confirmation. The apparatus disclosed in the patent includes means for properly positioning a coin face to be photographed so that the photograph will record the condition of the coin face. The apparatus provides indexing or reticle lines for locating the position of aberrations on a coin face so that the coin can be readily compared to the photograph, should such be necessary for identification of the coin.